1. Field of the Invention
The present invention relates to a lead frame, a method of manufacturing the lead frame, a semiconductor device using the lead frame and a method of manufacturing the semiconductor device. More particularly, the present invention relates to the formation of an external terminal of a resin sealing type semiconductor device.
2. Description of the Related Art
Recently, electronic equipment such as a personal computer and cellular phone has been downsized. According to this tendency of downsizing electronic equipment, electronic parts are highly densely assembled. Therefore, in the field of a semiconductor device such as a diode and transistor, in order to reduce the assembling area, a face assembly type semiconductor device is widely used.
In this face assembly type semiconductor device, in order to reduce the manufacturing cost, concerning the form of a package, a resin sealing type semiconductor device is widely used because the material cost is low and the productivity is high.
For the object of reducing the size of a semiconductor device, the following technique is proposed. A lead frame, in which a protrusion is formed in a region that becomes a lead, is used, and a semiconductor chip is mounted on the lead frame and electrically connected. After the completion of resin sealing, the lead frame is removed together with the resin by polishing from the reverse side while leaving this protrusion so that the thickness can be reduced, and then dicing is conducted so as to divide it to individual semiconductor devices.
As an example, the semiconductor device shown in FIGS. 11A to 11C is proposed. Concerning this semiconductor device, refer to Patent Document 1. This semiconductor device is formed as follows. A semiconductor chip is fixed to and electrically connected to a lead frame, and then resin sealing is conducted from the reverse side of the lead frame. Then, the semiconductor chip 72 is fixed onto the lead frame. A frame comprising the islands 61, 61A, which become electrodes used for an external connection, and also comprising a plurality of lead terminals 62, 63, 62A, 63A, which become the other electrodes used for an external connection of the semiconductor chip 72 fixed to the adjoining island, is fixed to the semiconductor chip 72 being attached with conductive paste on the islands of the plurality of lead frames arranged in the row direction by the connecting bar and electrically connected to the adjoining lead terminal. A resin layer is formed on the lead frame so that the semiconductor chip and the lead terminal can be covered and reverse faces of the island and the lead terminal can be exposed. The islands, to which the semiconductor chips are fixed, and the semiconductor chips are individually divided into individual pieces in a region surrounding the electrically connected lead terminal.
[Patent Document 1]
Unexamined Japanese Patent Publication No. Hei-10-313082
According to this technique, it is possible to downsize the semiconductor device. However, on the contact face of the resin sealing type semiconductor device with the printed board, that is, on the reverse side of the semiconductor integrated circuit device, since the resin face and the lead terminals, which become the external terminals, are on the same plane, even when a small deviation of the size is caused, it is impossible to positively connect with the circuit pattern on the printed board, which could cause an imperfect contact.
In order to protrude the lead terminals, it is necessary to provide a plating process in which the bumps (the protruding portions) are formed after the completion of dicing, which increases the man-hour in the manufacturing process.
The present invention has been accomplished in view of the above actual circumstances. It is an object of the present invention to provide a highly reliable thin type semiconductor device capable of being easily manufactured.